Multichannel, surface parallel, zonal transducer systems are often used for controlling light weight adaptive optics. In one approach a MEMS device consisting of individual actuators of piezoelectric, ferroelectric or capacitive material are mounted on one side of an optical membrane. Optical coatings are often applied to the optical surface on the other side of the membrane. This approach suffers from a number of shortcomings. The mass of the actuators themselves suspended from the membrane distort the membrane. And the coatings can cause further stress and deformation. The amount of motion is limited, usually no more than 1½-2 um, and often is not sufficient to compensate for even these inherent deformations let alone other environmentally caused deformations. In addition these devices are made by building up a number of their layers on the membrane. Each application of a layer thermally cycles the membrane and actuators inducing stresses. And these actuators are ultimately not more than 15 um thick and therefore not capable of applying very much force. Typically the largest optical element that can be made this way is about 10 mm and they require high voltage drives, e.g. 300V.
In another approach using a substrate support the actuators are mounted spaced from the membrane or optical surface of the substrate and oriented generally parallel to the optical surface or membrane U.S. patent application Ser. No. 10/730,412, filed Dec. 8, 2003, entitled Integrated Zonal Meniscus Mirror, by Mark A. Ealey herein incorporated in its entirety by this reference. This approach requires discrete actuators and a support substrate. The stiffness of the substrate limits the amount of motion that can be applied to the substrate to shape or adapt the optical surface.